Justification:
Given the impact of habitat loss within the range of this species, in addition to live capture, it is likely that M. murinus is currently in decline. The geographical range of this species is currently relatively extensive, and so despite these threats, the species is still thought to be widespread, common and adaptable. Based on these premises, M. murinus is listed as Least Concern. Further information on hybridization, population status, habitat loss, and threats may warrant listing this species in a more threatened category in the future.

This species is distributed from about the Onilahy River along the entire western coast to the north perhaps as far as Ankarafantsika National Park. A disjunct population is also found in the southeast up to the littoral forests of the Mandena Conservation Zone (Mittermeier et al. 2008).

M. murinus is adaptable, widespread, and abundant, making it one of the least threatened of Madagascar’s lemurs. Recent density estimates range from 167 individuals/km2 (Ampijoroa forestry station adjacent Ankarafantsika National Park) to 180 individuals/km2 (Kirindy Forest/CFPF), suggesting that this species remains one of Madagascar’s most abundant small mammals (Radespiel 2000, Eberle and Kappeler 2002, P. Kappeler pers. comm.).M. murinus hybridizes withM griseorufus in southeastern Madagascar in two ecologically different contact zones. One hybrid zone is located in the transitional zone between dry spiny bush and humid littoral forests south of the southern tip of the Anosy Mountain Range west and east of Ankilivalo (S 25.112 ,E 46.689) (Gligor et al. 2009). The second hybrid zone is located in the western rainshadow of the Anosy Mountain Range where there is a mosaic of dry spiny bush and gallery forests. Most hybrids in this area have been observed at Mangatsiaka (S 24.9660, E 46.5574) (Hapke et al. 2011).

M. murinus inhabits lowland tropical dry forest, sub-arid thorn scrub, gallery forest, spiny forest and secondary forest formations. They are also present in plantations and degraded habitats (Ganzhorn and Schmid 1998). Studies at Ampijoroa also indicate that individuals may take shelter in three to nine different tree holes within their range and remain in a given shelter for several days in succession. Females tend to share nests with several conspecifics, while males tend to sleep alone (Radespiel et al. 1998). The sexes also differ in home ranges, as male home ranges tend to be larger, especially during the mating season (Buesching et al. 1998, Radespiel 2000, Eberle and Kappeler 2002). After a gestation of approximately 60 days, typically two young are born.

In the west of the range, habitat is being lost due to yearly burning for slash-and-burn and cattle grazing. The Mandena habitat is completely destroyed. Although M. murinus is reported to inhabit secondary forests and degraded habitats, there is some evidence that decreased habitat quality may have adverse effects on population dynamics. According to Ganzhorn and Schmid (1998), fewer large tree holes in secondary forests result in fewer opportunities to save energy through periods of torpor, and may increase levels of stress and mortality. Live capture to supply the local pet trade is also a threat to this species, especially in the southern and northern parts of its range. Mining also poses a threat to this species.

This species is listed on CITES Appendix I. It is present in eight national parks (Andohahela, Ankarafantsika, Baie de Baly, Isalo, Tsingy de Namoroka, Vohibasia, Kirindy Mitea and Zombitse), five special reserves (Andranomena, Bemarivo, Beza-Mahafaly, Kasijy, and Maningoza), the Berenty Private Reserve, and other privately-protected forests within the Mandena Conservation Zone. Also occurs in Kirindy Classified Forest (Mittermeier et al. 2008). According to ISIS (2009), this species is maintained in a number of captive collections in Europe and the United States, the international studbook held by the Duke University Primate Center.